In the operations of laser gyros, geometric variations due to temperature, manufacturing misalignments and operation environments cause thermo-elastic deformations of their components, which lead to changes of the area and perimeter of their resonator block. The ray transfer matrix in the geometric optics can be utilized to predict the optical ray paths on the basis of the temperature environments as well as the misalignment of mirrors. The distance and orientation (or slope) at the arbitrary plane inside the resonator along the ideal optical path can be calculated from the chain multiplication of the ray transfer matrix for each optical component in one round trip. The geometric scale factor variations can be corrected by the piezoelectric actuator based on the design parameters of optical path control in the resonator. For the effective corrections of it, the feasible designs of piezoelectric actuator are required. This paper presents the numerical formulation of the elastic behavior of each piezoelectric actuator and the numerical formulations are verified through the comparisons with the results of finite element simulation and experiments.